Glossary of Drinking Water Tests

(Maximum Contaminant Level -= 4.0 mg/L)

(Secondary Maximum Contaminant Level = 2.0 mg/L)

Fluoride is naturally occurring in the bedrock of New Hampshire. Since fluoride is tasteless, colorless and odorless, the only way to determine its concentration is through laboratory analysis. The Centers for Disease Control (CDC) have recommended 1.0 to 1.2 milligrams per liter (mg/L) as the optimum beneficial concentration of fluoride in drinking water for dental protection.

Below 0.5 mg/L, there is little tooth decay protection. Above 1.5 mg/L, there is little additional benefit. In the range of 2.0 to 4.0 mg/L of fluoride, staining of tooth enamel is possible. At concentrations above 4.0 mg/L, studies have shown the possibility of skeletal fluorosis as well as the staining of teeth. In its most severe form, skeletal fluorosis is characterized by irregular bone deposits that may cause arthritis.

Download our Fact Sheet on Fluoride